A young, pony-tailed apprentice from Deptford may have earned himself a small but decisive place in this year's general election campaign.

For a brief moment last week a look of panic swept across David Cameron's face as the apprentice fired pointed questions about Margaret Thatcher's record during an open session at Lewisham college.

A handful of other apprentices then started to barrack Cameron as he took questions in the south-east London college's carpentry room.

Within a few minutes Cameron had regained his composure, eventually earning a thumbs up from the apprentice as he said politics should be lively.

Later that night, in the more comfortable surroundings of the Tories' first election rally, Cameron indicated that his experience in Deptford was his equivalent of John Major's soapbox moment.

The former prime minister famously found his stride in the 1992 campaign when he started answering unscripted questions from a soapbox.

"I have made a big decision about this election," Cameron told the rally in Shoreditch last Monday night. "I want lots of meetings like this. Not with autocues and lecterns and soundbites and speeches, but real meetings where I set out what is wrong in this country and how we are going to put it right."

Tory strategists, who have experienced a nervous month as they watched a narrowing of their decisive poll lead, believe that Cameron live and unplugged will be the defining feature of their campaign. The Conservative leader will display in these meetings across the country what his strategists believe is his most important election asset – authenticity.

"Authenticity is key to this election," one senior Tory strategist said.

"That is why we are so confident. People sniff you out."

The Tories believe Cameron can claim the mantle of authenticity for two fundamental reasons. First, the Tory approach to government, which involves devolving vast layers of powers, lends itself to spontaneous debate with voters.

"Gordon Brown is not capable of doing these open meetings," another senior Tory strategist said. "Our meetings are all about breaking down barriers. Brown is all about putting up barriers."

Cameron's easy connection with voters only works, the Tories say, thanks to the second reason why he can lay claim to authenticity. They claim that on the economy, the most important issue of the election, Cameron has a record to defend and even laud.

Labour is likely to scoff at this because the Tories' recent wobble was caused, at least in part, by surprise at Britain's weak economic recovery that led Cameron to tone down his rhetoric on spending cuts. But Cameron's team are adamant that he has been consistent in challenging the right and left on the economy. George Osborne, the shadow chancellor, saw off the right in 2006 by pledging to place fiscal responsibility before tax cuts.

The change also marked a challenge to Labour. Osborne had no choice, because the public finances were "screwed even then", according to one strategist who points out that Brown has only recently acknowledged the scale of Britain's record £178bn fiscal deficit under Tory pressure.

"We have been totally consistent," the strategist said. "Imagine the mess if we had gone along with the previous Tory position. We have also had an unbelievable strategic success in winning the argument on debt in the past year. It forced Brown to drop his favourite nonsense about Labour investment versus Tory cuts."

Another senior figure said: "Brown's position on cuts is not authentic. Think how long it took him to say the word cut."

This focus on Brown shows how the Tories will do more to spell out what they see as the dangers of a fourth-term Labour government. "You will see a very clear presentation of the choice – an explanation of our plans for the future but also a very clear explanation of why people will be making a huge mistake if they vote for five more years of Brown."

The Tories are careful to say that they are not turning negative.

William Hague, the shadow foreign secretary, has advised Cameron not to repeat his mistake in 2001, when he turned voters off by warning that Labour was turning Britain into a "foreign land".

Attacks will therefore be made with a light touch. Cameron gave a taste of this last week when he mocked Brown's claim that he has seen Britain through the recession. "Children up and down the country have got a new excuse now. How did the A-levels go? 'Oh I saw my way through my A-levels.' It is just unbelievable."

Cameron's ease in front of audiences suggests he has found his stride after his party's recent wobble, which is being blamed on four main factors.

These are: a fear that the Tories' warnings of early spending cuts were frightening voters; a feeling that the campaign lacked leadership because of Osborne's dual role as campaign director and shadow chancellor; polling evidence showing that the 38-year-old Osborne is seen as too young and inexperienced to be a credible chancellor; and a failure to simplify the Tory message.

"The wobble was the equivalent of a bad rehearsal," one shadow minister said. "That has been useful. These people have been told: stop arguing and work out who is in charge."

Yet many Tories say there is still one key weakness: Osborne. One highly influential figure says: "George Osborne is a terrible weakness on the doorstep and in the polling. It is too late to change him. But if the economy is the number one issue and your principal economic spokesman is weak, then you have a problem."

One shadow minister thinks there is a deeper problem: "I'm not sure we have the headline sorted out."

The leadership hopes it will answer this when it launches the Tory manifesto next month. This will have two key themes – restoring the public finances and reforming public services. Underpinning the policies will be the three core ideas built up since Cameron became leader in 2005: that Britain suffers from a broken economy, a broken society and broken politics.

The emphasis of the manifesto will once again be on authenticity, though this gives the Tories a problem in the world of endless news cycles. "People should say they recognise a lot of this," one senior figure says.

If the media turn their noses up at the manifesto, on the grounds that it is not new, the Tories say they will be delighted. "This is an evolution of what we have done," another senior figure said. "There is not a magic new thing."

When Gove manned a picket line

He may not enjoy the reminder, but the Twittersphere was delighted with the publication of a photograph showing that Michael Gove once manned a picket line. Gove, who last week led a vigorous attack on Labour's links with the trade union Unite, is shown leaning on a National Union of Journalists placard in an industrial dispute while he worked for the Aberdeen Press and Journal. Gove said last week that Gordon Brown was "in thrall" to Charlie Whelan, political director of Unite. He added that his experience on the picket line had taught him that strikes were wrong because they end up hurting workers.

If the Conservatives win the election, most of their MPs will be first-timers, part of a new elite that includes more women, gay and non-white candidates than ever before. From the chick-lit author to the black farmer, Julian Glover investigates how deep the reinvention really runs